Molecular data on vectors and reservoir hosts of zoonotic cutaneous leishmaniasis in central Iran

Due to the increasing number of positive cases of cutaneous leishmaniasis with occurrence of new foci, a study was carried out to investigate on vectors and reservoirs of the disease in the Shahrood district, central Iran during 2005-2006. Sandflies and rodents were collected using sticky papers and Sherman live traps respectively More than 1700 sandflies were collected and identified, mainly Phlebotomus papatasi species. RAPD-PCR analysis of sandflies showed that 10% of P. papatasi and 4.2% of P. caucasicus were naturally infected with Leishmania major. Two species of rodents, potential reservoirs, Rhombomys opimus (92.5%) and Nesokia indica (7.5%) were trapped in the district. Microscopy identification from rodents confirmed that 91.9% of the Rhombomys opimus were positive to amastigotes. Species identification of isolated parasites revealed Leishmania major DNA in the infected Rhombomys using RAPD-PCR technique. This epidemiological data highlight the importance of the disease in the region and could help people involved in control programs.

Isolation and characterization of pathogenic Leishmania turanica from Nesokia indica (Rodentia, Muridae) by PCR-RFLP and ITS1 sequencing in Iran

Zoonotic cutaneous leishmaniasis, primarily an infection of desert rodents, is an important endemic disease in some parts of Iran. In spite of reporting Leishmania infection in Nesokia indica microscopically, its role remains unclear in Iran. We report the first natural infection by Leishmania turanica in a wild-caught N. indica in the west part of Iran, near the border with Iraq. The evidence is in the form of PCR-RFLP testing based on internal transcribed spacer 1 (ITS1) rDNA with HaeIII enzyme and ITS1 sequence analysis. This isolate was highly pathogenic in BALB/c mice and golden hamsters and caused lethal systemic infection in the former.

PCR based on identification of vectors of zoonotic cutaneous leishmaniasis in Shahrood District, central of Iran

A study was made in rural region of Shahrood city, Semnan province in the central of Iran during 2005 to investigate of vectors of zoonotic cutaneous leishmaniasis. Sticky traps and an aspirator were used for collecting of sandflies. Three species of Phlebotomus papatasi, P. caucasicus and Sergentomyia sintoni were collected and identified and the first species was dominant (53%). Nested PCR method were employed for identifying of isolated parasites of dissected female of sandflies. Among the dissected sand flies 3 out of 24 (12.5%) Phlebotomus papatasi and 2 out of 48 (4.2%) Phlebotomus caucasicus were found naturally infected with promastigotes. Species-specific amplification ofGiemsa staind promastigote slides revealed specific PCR production of Leishmania major DNA in the infected P. papatasi and P. caucasicus sand flies. Having high prevalence and infection rate provide enough evidence to incriminate of P. papatasi as the main and proven vector of cutaneous leishmaniasis to human in the region and the species of P. caucasicus play the second role for maintenance of disease between rodents.

Unresponsiveness to Glucantime treatment in Iranian cutaneous leishmaniasis due to drug-resistant Leishmania tropica parasites

BACKGROUND

Recent circumstantial evidence suggests that an increasing number of Iranian patients with cutaneous leishmaniasis are unresponsive to meglumine antimoniate (Glucantime), the first line of treatment in Iran. This study was designed to determine whether the clinical responses (healing, or non-healing) were correlated with the susceptibility of Leishmania parasites to Glucantime.

METHODS AND FINDINGS

In vitro susceptibility testing was first performed on 185 isolated parasites in the intracellular mouse peritoneal macrophage model. A strong correlation between the clinical outcome and the in vitro effective concentration 50% (EC50) values was observed. Parasites derived from patients with non-healing lesions had EC50 values at least 4-fold higher than parasites derived from lesions of healing patients. A selection of these strains was typed at the molecular level by pulsed-field gels and by sequencing the pteridine reductase 1 (PTR1) gene. These techniques indicated that 28 out of 31 selected strains were Leishmania tropica and that three were Leishmania major. The L. major isolates were part of a distinct pulsed-field group, and the L. tropica isolates could be classified in three related additional pulsed-field groups. For each pulsed-field karyotype, we selected sensitive and resistant parasites in which we transfected the firefly luciferase marker to assess further the in vitro susceptibility of field isolates in the monocyte cell line THP1. These determinations confirmed unequivocally that patients with non-healing lesions were infected with L. tropica parasites resistant to Glucantime. Additional characterization of the resistant isolates showed that resistance is stable and can be reversed by buthionine sulfoximine, an inhibitor of glutathione biosynthesis.

CONCLUSIONS

To the authors' knowledge, this is the first report of proven resistant parasites contributing to treatment failure for cutaneous leishmaniasis and shows that primary Glucantime-resistant L. tropica field isolates are now frequent in Iran.

Epidemiological aspects of canine visceral leishmaniosis in the Islamic Republic of Iran

An epidemiological study to examine the sero-prevalence of zoonotic visceral leishmaniosis (ZVL) among domestic and wild canines in endemic foci of Iran was carried out during 1999-2003 to assess the distribution of the disease and the possible association between infection in dogs, wild canines and people. Anti-leishmanial antibodies were detected by the direct agglutination test (DAT). Parasitological study was performed for all captured wild canines and were detected in some of the seropositive dogs with specific clinical signs (n=107). Serum samples (n=1568) were collected from domestic dogs in villages that are known endemic foci of human visceral leishmaniosis (HVL). Wild canine sera were collected from jackals (Canis aureus, n=10), foxes (Vulpes vulpes, n=10) and wolves (Canis lupus, n=10). Of the 1568 serum sampled collected from domestic dogs, 222 (14.2%) were positive by DAT (1:320 and above). No statistically significant difference was found between male (15.2%) and female (11.8%) sero-prevalence (P=0.083). Dogs of 8 years and above showed the highest sero-prevalence (40.6%). Only 23.9% of the seropositive domestic dogs had clinical signs. Parasitology and serology tests that were performed in 30 wild canines showed 10% these animals were infected by Leishmania infantum. Ten out of 11 Leishmania spp. isolated from the dogs and wild canines were identified as L. infantum and one other as L. tropica by molecular and biochemical techniques. For the first time in Iran, L. infantum and L. tropica were isolated from viscera of both a wolf and a domestic dog.

Characterization of Leishmania infection in rodents from endemic areas of the Islamic Republic of Iran

Between 1991-2000, Leishmania species were isolated and characterized by isoenzyme and molecular analysis from rodents caught in various parts of the Islamic Republic of Iran. In areas endemic for cutaneous leishmaniasis, parasites were observed by direct microscopy in smears from 18.6% of 566 specimens. L. major was isolated from 4 species:Rhombomys opimus, Meriones libycus, Tatera indica and Mer. hurrianae. L. turanica was isolated from R. opimus for the first time in this country. In endemic areas of visceral leishmaniasis, parasites were observed in liver and spleen from 13.7% of 504 rodents. Two species were positive on culture; promastigotes isolated from Mer. persicus were characterized as L. donovani zymodeme LON50 and from Mesocricetus auratus as L. infantum LON49

Characterization of Leishmania infection in rodents from endemic areas of the Islamic Republic of Iran

Between 1991-2000, Leishmania species were isolated and characterized by isoenzyme and molecular analysis from rodents caught in various parts of the Islamic Republic of Iran. In areas endemic for cutaneous leishmaniasis, parasites were observed by direct microscopy in smears from 18.6% of 566 specimens. L. major was isolated from 4 species: Rhombomys opimus, Meriones libycus, Tatera indica and Mer. hurrianae. L. turanica was isolated from R. opimus for the first time in this country. In endemic areas of visceral leishmaniasis, parasites were observed in liver and spleen from 13.7% of 504 rodents. Two species were positive on culture; promastigotes isolated from Mer. persicus were characterized as L. donovani zymodeme LON50 and from Mesocricetus auratus as L. infantum LON49.

Vaccine trial against canine visceral leishmaniasis in the Islamic republic of Iran

Sixteen dogs were randomly divided into four groups. Group 1 received autoclaved Leishmania infantum vaccine with BCG. Group 2 received autoclaved L. major vaccine with BCG. Group 3 received BCG alone and Group 4 received normal saline. Dogs received the vaccines intradermally three times each at 30-day intervals. All dogs were tested at 2-month intervals with the leishmanin skin test and anti-Leishmania ELISA. Ninety days after the third dose, each dog received an intraperitoneal challenge of 2.5 X 10 [6] infective promastigotes of L. infantum. Necropsy was performed on all dogs to investigate for parasites. All of the dogs in the unvaccinated groups were infected with L. infantum but of the dogs in the vaccinated groups, only one dog was infected